<cdk-tree [dataSource]="dataSource" [treeControl]="treeControl">
  <cdk-tree-node *cdkTreeNodeDef="let node" cdkTreeNodePadding class="example-tree-node">
    <button mat-icon-button disabled></button>
    {{node.filename}}:  {{node.type}}
  </cdk-tree-node>
  <cdk-tree-node *cdkTreeNodeDef="let node; when: hasChild" cdkTreeNodePadding class="example-tree-node">
    <button mat-icon-button [attr.aria-label]="'toggle ' + node.filename" cdkTreeNodeToggle>
      <mat-icon class="mat-icon-rtl-mirror">
        {{treeControl.isExpanded(node) ? 'expand_more' : 'chevron_right'}}
      </mat-icon>
    </button>
    {{node.filename}}:  {{node.type}}
  </cdk-tree-node>
</cdk-tree>
